The magnets of a secondary element are frequently made of relatively brittle materials. For this reason, and because of their strong magnetic forces, which strongly attract, for example, iron filings, the magnets are frequently shielded from the environment.
EP 1230727 B1 describes protecting the magnets of a secondary element by means of cover strips made of a plastic material and arranged laterally along the magnet track. This plastic material is flexible and can also be adapted to curved magnet tracks. The magnets are additionally protected by a covering tape that is placed on the magnets and also rests laterally on the cover strips, so that the magnets are shielded from the environment on all sides. However, in these secondary elements, the positioning of the magnets on the magnet support is a very complex process.
KR 20110080879 A describes placing the magnets into a grid-like frame of plastic that has previously been glued to the magnet support. The frame helps in the proper positioning of the magnets and protects the magnets. Again, a cover is mounted on the frame and the magnets, so that the magnets are completely enclosed from the environment. Here too, the magnets are covered by a multi-part cover, which makes assembly more complex.
DE 102007020057 A1 describes linear motors where the primary element and the secondary element include laminated cores, the individual laminations of which form cooling channels once assembled. This eliminates the need for additional cooling serpentines or machining steps for creating the cooling channels. As usual, the laminations are oriented such that their plane lies parallel to the direction of the magnetic field in the air gap of the motor so as to suppress eddy currents as effectively as possible.